Video Analysis: Providing a success score for a of a student carrying out a specific task
You have not described exactly what the tasks will be, but there are some open source libraries for real time pose tracking. For example, OpenPose is one that can be configured to track the body, the hands and the face. However, this is only going to give you predicted pose information for each frame. If the subjects are meant to be doing specific tasks, e.g. picking up objects and moving them, OpenPose won't help and you may need to do further image recognition/analysis or object tracking in order to interpret what is going on.